2019年珠海市登革病毒传播影响因素分析

目的 根据2019年珠海市登革病毒（DENV）的流行病学数据统计分析、DENV包膜蛋白（E）基因序列测定、登革抗体水平回顾分析及蚊媒密度监测，分析珠海市登革病毒传播的影响因素。方法 收集2019年登革热流行病学资料开展统计学分析；采集登革热临床诊断病例的血清标本，提取RNA，用RT - PCR方法检测，阳性标本针对E基因测序分型，构建进化树分析样品来源；采集2017—2019年珠海市200份/年的健康人群血清进行登革热抗体IgG检测；开展珠海市2019年蚊媒监测。结果 珠海2019年DENV流行的血清型主要为DENV - 1型，全部属于基因Ⅰ亚型，并分布在3个不同的分支上，分别与2017年越南、2015年柬埔寨，2014年马来西亚、新加坡，2014、2012年斯里兰卡等流行株高度同源；少数感染DENV - 2与DENV - 3病例均为输入病例，核酸序列与分别输入国的流行株序列高度同源；登革病毒IgG抗体阳性率逐年提高（2017年的1.5%到2019年12%）；2019年全市BI指数月平均值处在1.4～3.6之间。结论 目前珠海市登革病毒流行方式属于输入性引起的本地暴发流行，鉴于珠海登革疫情预警机制和蚊媒密度监测等工作推断，我市未来几年大范围暴发本地登革热疫情几率不高。

Influencing factors of dengue virus transmission in Zhuhai city in 2019

Objective To investigate the influencing factors of dengue virus(DENV) transmission in Zhuhai city in 2019 based on the statistic analysis, sequences of E gene of DENV, retrospective analysis of DENV antibody, and mosquito density monitoring. Methods Epidemiological data of dengue fever in 2019 were collected for statistical analysis. Serum specimens from clinically diagnosed cases of dengue fever were collected for RNA extraction and detection using RT-PCR. The positive samples were sequenced and typed according to E gene, and phylogenetic tree was constructed to analyze the source of samples. Sera of 200 healthy people per year were collected for dengue antibody IgG testing from 2017 to 2019. Mosquito surveillance was conducted in 2019 in Zhuhai. Results The serotype of DENV epidemic in Zhuhai in 2019 was mainly DENV-1, all belonging to genotype I subtype and distributed in three different branches, which were highly homologous with the epidemic strains in Vietnam and Cambodia in 2017 and 2015, Malaysia and Singapore in 2014, and Sri Lanka in 2014 and 2012, respectively. The few cases infected with DENV-2 and DENV-3 were imported cases, and the nucleic acid sequences were highly homologous with the sequences of the epidemic strains from the respective importing countries. The positive rate of dengue virus IgG antibody rose from 1.5% in 2017 to 12% in 2019. The monthly average of BI index in 2019 was between 1.4 and 3.6. Conclusion The current epidemic mode of dengue virus in Zhuhai is local outbreak epidemic caused by importation. Given the early warning mechanism of dengue epidemic in Zhuhai and mosquito density monitoring, it is inferred that the chances of a widespread local outbreak of dengue fever in Zhuhai are not high in the next few years.